Conventional system for originating and receiving telephone calls, particularly long distance or international telephone calls, typically involve routing through the facilities (e.g., switches) of a local service provider (LSP), i.e., local exchange carrier (LEC) in the United States. With respect to outgoing calls placed from a subscriber location, the LSP switch serving the subscriber's customer premises equipment (CPE) senses an off-hook condition and extends dial tone. Alternatively, the CPE may extend dial tone to the end user, analyze the dialed digits, seize an appropriate trunk for routing the call and send the dialed digits to the LSP switch. When the dialed digits are received in the LSP switch, any features associated with the originating subscriber, such as speed dialing, are applied to the call, and the call is then routed to the desired destination. If the call is a long distance call that is thereafter routed to a long distance or interexchange carrier (IXC) such as AT&T, then the IXC will pay the LSP for servicing the call, in the form of an "access charge", and the subscriber pays the IXC for the call, and pays the LSP and/or IXC for any originating features provided.
With respect to incoming calls received at a called party location, a similar condition prevails. Long distance calls destined for a called party are routed by the IXC to the terminating switch or associated tandem switch operated by the LSP that services the called party location. At the LSP terminating switch, any features associated with the called subscriber location, such as call forwarding and distinctive ringing, are applied to the call, and the call is then completed. Again, the IXC will pay the LSP for servicing the call, in the form of an "access (or egress) charge", and the subscriber will pay the LSP for any terminating vertical services provided.
One prior art system has attempted to allow the CPE to exchange information directly with the IXC switch while bypassing the access/egress charges associated with routing calls through LSP switches. U.S. Pat. No. 5,533,111 issued to Schlanger, on Jul. 2, 1996 and assigned to AT&T Corp., herein incorporated by reference, utilizes a "virtual pipe" to establish a virtual connection between the CPE and the IXC switch through the LSP network. Once the virtual pipe is established, the subscriber can originate calls to the IXC switch without being detected by LSP and without affecting the connection that exists through the LSP switch. The Schlanger system, however, suffers from routing the call through the LSP switch and, therefore, relying on the LSP to provide the hardware connection at reasonable access rates.
In addition to being connected through a traditional connection to a LSP switch, a business' CPE, such as a private branch exchange (PBX), can also be connected through a nodal connection to an IXC switch, for example a 4ESS.TM.. A nodal connection is a direct transmission path from the CPE to the IXC switch without being routed through a LSP switch. By taking advantage of the direct connection between the CPE and the IXC switch and by allowing the IXC switch to support at least a subset of local call functionality, the disadvantages of the prior art can be overcome while allowing the IXC to route some calls as local calls that otherwise would be routed to the LSP switch at toll rates.
Several problems, however, prevent an IXC switch from easily supporting at least a subset of local call functionality to customers connected by a nodal connection. First, the IXC switch must distinguish a local call from a toll call from any other type of call. Typical interconnection arrangements between carriers define higher access rates for toll calls delivered to an LSP for completion, compared to the corresponding rate for local calls. Because an IXC switch supporting at least a subset of local call functionality would receive both toll calls and local calls, the IXC switch must distinguish a local call from a toll call from any other type of call or else the IXC switch cannot support routing with local access rates and would be limited to the IXC toll access rates with the LSP.
Second, to develop competitive offers to customers, an IXC switch supporting at least a subset of local call functionality must classify a call as local or toll for customer billing and billing related features independent of whether a call is eligible for delivery to the LSP network for completion at local or toll rates. For example, a call eligible for delivery to another LSP for completion only at toll access rates may be billed to the customer as either a local or toll call, depending on the calling offer the IXC has extended to the customer. Similarly, a call eligible for delivery to the LSP for completion at local access rates may be billed to the customer as either a local or toll call, depending on the calling offer the IXC has extended to the customer.